The plane does come as a pleasant surprise (to me). If it is shanzhai engine, would Russia again dispute the license rights?
Could potentially cause problems snagging any export deal, though it's clearly not the PRC's priority at this time. But it all comes down to prior license agreements, I suppose. Russians aint' dumb. It's common knowledge that in the past they just supplied 2ne-tier tech for PRC to reverse-engineer to its heart's content. But in the future, Russia may focus on export control (if not already), profit sharing and joint product development.
It's already engaged in that with Israel, India, and European players such as France. Granted, India is so far doing more funding than developing - but "indigenization" is no less a buzz word there.
So is Pakistan, for that matter - focusing on licensed and unlicensed productions. Only Saudi Arabia can and will buy the latest and greatest, although their ability to sustain anything beyond a week should Uncle pull parts support is highly doubtful. Heck, we don't even know if their civilian side will function if all the South Asians went home (based on stories told to me).
Based on what little understanding I have - key military tech are seldom patented for one reason or another.
In Uncle's own house, things are just as murky.